One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,11)(8,9)(10,12) involution — undirected(2,3)(6,9)(10,11)(13,14,18,22)(15,21,17,19)(16,24,25,27)(20,26,28,23)(1,2,4,3)(13,15,18,17)(14,19,22,21)(16,23,25,26)(20,24,28,27)(1,3,4,2)(13,16)(14,20)(15,23)(17,26)(18,25)(19,24)(21,27)(22,28)(5,7,8,12)(6,10,9,11)(13,15,18,17)(14,21,22,19)(16,23,25,26)(20,27,28,24)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.